Booster pump



Dec 22, 1942 R. R. CURTIS 2,306,302-

BOOSTER PUMP Filed Aug. 14, 1941 2 sheets-sheet 1 WM @l I n /0 ,Dea 22, 1942. R R, CURTls 2,306,302

` BOOSTER PUMP Filed Allg'. -14, 1941 2 Sheets-Sheet 2 IZ I f-Z f dicated'by .the line 'c vthe boos'tferfpump 'of this invention may Y. the bottom wall of turn is connected pump will be tion itself, however, both as to its organization and manner of construction, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying l drawings, inr which:

Figure 1 is a fragmentary view in vertical cross section, with parts in elevation, of a portion of a fuel system embodying principles of the present invention and illustrating the operative relation-1 conditions of parts thereof under certain Figure 1 illustrate Figure 2 is a view similar to 3 portions cylindrical surface 204l` effect an agitation of the .cause a whirlpool action gas-fuel mixture flowing into the throat. These curved vane portions, lying within the throat, which is funnel-shaped and theagitated f uel is whirled in a cork-screw path yupwardlyand outwardly from the vanes.

ing the operative relation of parts thereof under certain other conditions; K

Figure 3 is an enlarged fragmentary transverse with parts -in elevation, as

III- III of Figure 1; Figure 4 is a bottom view movable throat member of the booster pump shown in Figure 2 and illustrating a modification of ,construction over the form shown in Figure 1; and

Figures 5 ,an'd 6 tratiiigl thefeonstructionwby which theA speed of l The portionof the fuel systemillustrated in Figures 1 and 2 generally comprises a-v fuel tankin elevation L of the *i yare diagrammatic views illusf f creased apoint is eventually reached in which the be varied.. l l

reduced atmospheric y mospheric pressure only,

This constant beating of the fuel effects an increased generation of gas and vapor bubbles over that which normally results from decreased at- 'I'he bubbles are carriedoutwardly and upwardly by the liquid stream y flowingin a, corirfscrewpath leaving only fully .liquid fuel atfthe axis ofthe throat to be pumped by thegfvane'sinto the outlet. When the aircraft is operated at low altitudes,

.4 the liquidfuel .is in' asubstantially vfully liquid ystate and the pumpimpeller merely delivers the fuel under pressureintof the delivery line. Howlliand a booster'pump assembly II, preferably but not necessarily, mounted on they of thetanla The fuel tank III .I3y carried within the tank. This* vent member fis illustrated als being provided inthe top wall ofthe tankaltliough it obviously can be posi-- onI the tankprovid'ed it is bottom wall has a vent member I2.posi vtioned above the surface of a pond-of liquid fuel vup,'. scattered bubbles U usal force; by

` liquid fuel` and are 401 dient of the f uel. therein and is preferably in the bottom Wall of ring I1 to receive fuel through the outlet opening Il. The throat member I1` rcal portion Il seated against the shoulder I6, of

the pump casing and the throat member is so has a reduced cylindril shaped as to provide a tapered mouth I9 and a.` a substantially cylindrical bore orpassageway 20 below the mouth. 2I in the pump casing below the throat member I1 opens into a discharge member 22 which in main fuel pump (not shown).

An internaivolute chamber y to a fuel delivery line-23 to the f The pump impellercomprises a hub 2|, a flange 25 and va series of curved vaines-2B connected to the flange. The 'impeller is secured to a' driving-v shaft 21 by a key (not shown) and a nut 28.

The outer periphery of'the impeller,y defined; by the ends of the venes 25, is` positioned between the throat member I1 and an annular flange portion 29 on the inside of the pump casing I5 in `order that the fuel owing into the p v delivered under the volute chamber 2| into A casing portion 30 houses'the driving shaft'21 and is conneotedto a source of motive power for driving the impeller, such as an electric motor lof a type which will be` described further hereinafter.

' As the liquid fuel I3 flows through the throat pressure through the delivery line 23. i

ing application. entitled craft fuel systems." Serial No; 352,064,l filed Augerated yby fthe impeller is vapors from, the

vtop of the from the axis of substantially fully liquid fuel'only is drawn downwardlythrough the axis of the whirlpool into the ever, as the altitude',range of the aircraft is in- Y pressure results in a generationand liberation of air, other fixed gases or liquid-fuel in the tank. This :conditions aggravatecr'as the altitude4 is inwcreased.

iWhen thefuel in the tank starts breakine v3i willappear in the pond of f uelvtbroughout thetan'k, As'soon'as the fuel andthe gas is subjected tothe'actionof centrifrotation 'of the curved impeller .bubbles rapidly separate from the 'thrown 'out to and concentrate around the periphery of thecylindrical surface 20 in the booster pump throat from where they rise and move upwardly through the fuel in blades 26,"the

- the Icork-'screw path vin thetan1 4along a Path ysubstantially parallel surface-I9, As shown with the' tapered throat in Figures l and 2, the bubble path ,gradually curves upward as the velocity of the liquid owing inthe corkscrew path decreases. I'he'bubbles finally reach the top surface ofthe fuel, where they escape from the l fuel pond into the atmosphere. This curved path is ata sufficient distance outwardly the pump assembly so that booster .pumpl f surface of'the fuel.

Whenl the bubbles 3| rise to the pond; they'break into the atmosphere above thejfuel and consequently are not drawn baci: into the downward flowing whirlpoolo'f fully liquified fuel entering the booster pump." f L c .i In this manner fully'liquid fuel is delivered by centrifugal actionof thepump. to the delivery line 2l and assures tlieproper volume of fuel into thesuctionside of a fuel pump for delivery ythereby' directly into the aircraft engine.

Thebooster.. pump constructionr so far describedisof the type disclosed in my co-pend- Booster 'pump for airust l10, y194.0. l .This booster pump construction is operated at 'a speed in whichthe pressure genusualiyl less than six pounds;l per'square inch, which pressure is sumcientfor assuring the flow of a propervolume of fuel intothe suction side of a fuel pump even though the aircraft be operated at high altitudes the cylindrical surface on the stationary However. when the aircraft is to be operated under conditions requiring higher delivery pressures or for emergency duty through partial or total failure of the engine fuel pump or the like, the increase in discharge pressure from the pump may be obtained by operating the pump impeller at'higher speeds. It has been found that discharge pressures greater than ten pounds per square inch are required for suchan vemer gency duty.

`The structure now to be described effects a discharge pressurel which is greater than the pressure resulting from an increase in speedv only.

As best shown in Figures 1 and 3, a ring member 35, having an inner diameter substantially the same as the diameter at the widest end of the' tapered throat surface i9, is lconnected to the throat member I1 'by means of at head screws or the like.

A plurality of flat elongate support members or columns 31 are circumferentially spaced around and have their lower ends connected to the ring member 35 by any such suitablek means as brazing, soldering or the like. A tubular sup.. port member and duct 38 also extends upwardly from and is connected to the ring 35 in a manner similar to the supports 31. While the support members 31 are illustrated as being three in number with only one duct'support member 38 and each spaced 90 apart, it is'to be understood that this number and spacing can be varied as desired, it only being necessary that suiiicient space be provided therebetween toy permit liquid fuel I3 to flow freely into the booster pump throat.

The upper ends of the support members 31 cach have an elongated substantially vertical edge 39 to which is connected, by brazing, solder or other means, a piston cylinder'40. It is to be noted that the tubular support member 38 extends upwardly into connection with the top portion of the piston cylinder 4i).

A conduit 4I for fluid flow isprovided through the pump casing I5, the throat member I1, the ring 35, the tubular support member 38 and the upper portion of the cylinder 40 to hydraulically connect the piston cylinder 4I)Y and the discharge volute 2l.

The upper end of the cylinder 4I) is internally I threaded as at 42 for receivingl therein an externally threaded end closure member 43. A piston 44 is slidably mounted in the cylinder 40 for a purpose now to be described.

It is to be noted that a at triangular member 45 is included between the ring member 35 and the tubular support member 38 with its outer edge 46 being substantially vertical. the lower inner edge 41 of each of .the support members 31 is-substantially vertical and yof approximately the same length as the edge 46 on the triangular member ,45. These edges act as guiding means or tracks for a movable throat member 48.

The upper portion 49 of the movable throat member 48 is substantially conical in shape with its sloping side walls having a plurality of open-v ings 50 therethrough. 'I'hese openings permit ow of liquid; fuel I3 into the booster pump throat. The sidewalls of the lower portion of the movable throat member 48 slope inwardly toward the axis thereof with the'inner peripheral surface being curved and the outer surface shaped to conform to the tapered surface I9 and throatmember I1.

The peripheral surface .52 on the movable throat member between its upper and lower por'- `tions. slidingly Vseats against the vertical guiding surfaces 45 and 41. The movabley throat v member is thereby guided for movement toward and away from thefstationary throat I1.

1 A shaft 53,;connected at one endito the movable throat member 48',` 'extends upwardly through thebottom wall of thelpiston cylinder impeller I positions. l

40 and its other end is connected to the piston 44 by means of a nut 54.

A coil spring 55.is seated Within kthe piston cylinder 40 between `the bottom wall thereof and the piston 44 for maintaining the piston and the movable throat member in their uppermost v As explained above, during normal operation ofan aircrafttheA discharge pressure of the booster pump is six pounds per squareinch or less. As shown in Figure 1, this pressure is exerted through the flow conduit 4I against the upped side of the piston 44. The coil spring is of a size sucient to exert a pressure of more than six but less than tenpounds per square inch against the piston 44. Consequently, the movable throat member 48 is maintained in its uppermost position or spaced from the stationary throat I1 as long asthe discharge pressure in the booster pump remains below the pressure of the coil spring.

As also shown in Figure 1, the lmovable throat member- 48, when spaced from the stationary throat I1, acts as a deflector for the bubbles 3l as they rise from within the throat I1.

As shown inFigure 5, an electric motor is carried by the shaft housing 30 and is'connected to the shaft 21 for rotation of the pump impeller. The electric motor 63 is energized by a source of electrical energy 6l and the degree of energization is controlled by a lrheostat member 62. The rheostat 62 is diagrammatically illustrated in Figure 5 as being provided with three settings. one

Similarly,

ISI

of which is an offposition in which the motor 60 is de-energized, an intermediate or low position in which the electric motor is energized at a speed sufficient for maintaining a discharge pressure of approximately six pounds per square inch, and a third or high position in which the speed of the electric motor is increased whereby the discharge pressure in the booster pump is raised above ten pounds per square inch. c

The rheostat `ISIZ in Figure 5` is illustrated as being in the intermediateipcsition in which the electric motor is .energized for a speedsufcient to maintain the discharge pressure at approximately six pounds per square inch. The booster pump parts are then positioned as shown in Figure 1.

Figure 6 illustrates the rheostat 62 as being in a high position in which the electric motor B0 is energized for higher speeds and the discharge pressure in the volute 2| is then raised above ten pounds per square inch. e This pressure 'is sufficient, as exerted through the conduit 4I, to force the piston 44 downwardly whereby the movable throat member 48 has moved into seated engagement on the stationary throat member I1. As the curved inlet throat 63 on theinside of the movable throat member 48 is smaller in diameter than vthe cylindrical surface 2401i the throat member I1,` a greater ycoverage ofthe length of each of the vanes 26 is effected. This greater coverage effects a more positive centrifugal action of the pump impeller and results in a further rise or low position'. the dischargep'ressurein the p11-m9. below ten pounds p er-'squareinch v .witnthe othert 'and the coil spring further outward vfrom whirlpool.v However, the fuel ini the throat tapered of the pump impeller.

'.vention'have been'l be understood that the `appended fau within.

I claim as' my invention: f

` prising athroat member' and having' anv inlet? opening smaller.rthan said l.' first inlet throat,

in discharge pressure necessary for duty'. As long as lthe discharge pressure tained vabovethe compression pressure emergeno'y is smain-- of the will bef reduced spi-ing' 5 5, the piston I4 willfholdthe movable@Y fahroat member I8 in Ithe positionasillustrated in Figure 2.

When the motor speed is-again-.re-.- hrowmg the rhe'ostat to its intermediate A mineddischa rigepressure' in 55 will `raisethepi'ston 4I and 10; in to the pump isthroii'gh the' movable throat member lii"to-their'fupperv most positions as illustrated-in-Fig'rel.

Separation ofthe gasbubbles.- 3l Y.froml' liquid',y

fuel when the parts are positioned as illustrated inv Figure 2, is the same as that illustrated. and describ'ed in Fgurel with 'the ilector member-will aidin the-downwardly ilowing opening caused by rotation the impene; blades wm urge-the bubbles-'engutherebetween so that entirely thoughth'e throatzopening It will l,iave provided afvaiable 'speed and .pressure more, the arrangement assernbl'y'v for separating 'gas and fiiel's'ystem for-aircraft. -f Further- 'in this invention provides vforati increaseindischarge pressure of the pump greater' than is eftected'only by a-change in speed embodiments only of this inill'ust'rated;r it'will, 'of course, invention 'should not be' limited thereto', `since many modifications maybe made and,I thereforeit is 'contemplated by the claims to cover all such modiilcations as the' 'true spirit and scope yof the present vimileparticular.

invention. V

assembly 'having an inlet throat outlet, the'- improvements com"- normally spaced' from ranged 1 fory seated; engagement y. "'toward''and-away from the"other,.andmeans sensitive tothe" 2discharge pressure ina-said pump for so moving said-one throat'member. r: 2`. I n" a pump assembly having an'inlet throat I anda`discharge' outlet, the' improvement s comde'ectingtrie-bubbles'. pump. through controlledpy whirlpool ac'tionin the; 'forurging onel of said' throatsjnto engagement omov ' larly outward from4 the axis of the booster pumpI andwill permitiully liquid fuel within the portion of tliepumpbetwe'en-the support members to be,

drawn downwardly through the restrictedsthroat.

` [The co'operat' gcyl'indri'cal'surfaces'onthe two throatmenibers effects a seal jillustrated'in the" tapered under and having a ilowv Bns-1a ASi yondlinlet 4,therein smaller aoasoa second inlet throat engageable with opening therethrough of small- .tha' Sidfrst'inlet threat.; Said inlet lysn'efdtsriermitw 0f u quid. inteen ,.pumpjnrough seid first; inlet throataridjpistonfrne s operable 'at a predetersaid pump formovprising a l ing" one' off said inl t, throats" into engagement 'rvat'whreby the .flow ofxliquid said second inletthroat. 3. In a pump-'assemblyhavingjaninlet throat .and a. disch a1 'g e outlet, the improvements comthroat having Van opening thereinsmaller thanfsaid first inlet throat',4 pressure means normally maintaining said throats in exception that'no,de, e spaced relation permitting flow of li'iu'id'mm the saidarst inletjtnreetgariq means 'theldischarge' pressure in ysaidv pump throat whensaidfdischarge prespressureof lsaid means-'whereby ntosaidpump is through said with he, .Other sure exceeds 'the the flow ,o f liquid 4. a'. pump VV'assembly having"v an; `iiile'tthroat anda 4disc,h arg'{z fo'utlet, theirnprovem'ent's comthroatl having opening nieanfsf normally "maintainingffsaid" throats in spaced. relation vwhereby "liquid flows into said pump'throughsaid.stinlet throat, 'and means Y. foperableby.'thedischargef pressiire of said pump L and in .opposltion to -one ofI said. throa lsaidsprln'grneans for urging into 'engagement with the 'eby'fliquid ows'into said pump ond inlet throat.

assembly having an inlet throat,

through said'fs' an impeller havng'blades with portions longitudinally overlappedby said inlet throat, and

i vr'novable means concentric with said throat for increasing tli'elongitudinally overlapped relation of said. inletjthroat and said blades for increasing the dischargefpressure of liquid pumped by thatv r threat opening, .and outof saidfthroatfopening' for` increasing the Aso pump and increase liquid. flowing'. into, gaseous bubblestherefrom, a "second inletfthroatymovable toward and away in than said rstl normally; maint outward direction'.

6. In a- 'pu rnp` assembiy hzitvingy an inlet throat, animpeller adjacent said inlet-' throat and having vane blades overlapped 'byjthe periphery of the a; hollow 'member movable into overlappi n:g.. of jthe'" vane blades whereby the discharge pressure off'nquiupumped by tnemades is increased,v and vmeans Vfor so moving said hollow member. A

l' 7'.' I n a'pump assembly having'an inlet throat,

animpeller' adjacent said inlet throatand having vane blades overlappedby the'periphery of the throat opening, a seoondv inlet throat sized for 'seatingon and 'extending into said first inlet throat to blades'to tl'iereb'y increase the discharge pressure -ofuquid -pumped' by the blades, and means een- -trolled by tliedischarge pressure ofgsaid pump for moving orieIoi saidthroats toward and away vfrom the other throat..

*18. Ay centrifugal booster pump .assembly comprising an inlet throat, an impellerfor agltating ,said tv throat for separating discharge outlet, a

from said-.iixfst inlebthroat', 'said second inlet throat having asmallerllquid iiowopening thereinlet throat, pressure means aining s a id throats in" s paced rend throat 'deilects in an bubbles rising from 1ation whereby Said :56C

the' sass??? restrictl the-throat opening. into the the overlapping of the vane Y ls-'openingintosaidpumpa ,l

centrifugal booster'piunp'for a fuel sys- `terri y-for'1sparating -gasl'from iaf gas-liquid' mixasoaeoa said rst throat and gas-free liquid ows throughthroat members'..t'ogether when the said rst throat, piston means, and a conduit connecting saidvpump'v discl'iarge` and said Lpiston engagementffwithi-f:saidiffirst throat :when the discharge pressure,exceeds-fthatFof'ithe pressure lmeans for.restricting'fthefsizevof the'liquid flow tof saidcoil spring 1 -v .i 1:12,. Afrliquid` pum assemblyfcomprisingrela-k tively movablesghollowthroatmembers-- movable n linto andout of telescopieengagement witheach pressure in the greater than the pressure other to vary thesizevofl` the -inletopening-into v.the pump',. a rotatable if impeller having .blades foverlappedfby -thezinlet opening-Muthapump deture, comprising a vcasing'."Jzielning:a` discharge tapered throat in said inlet, an impeller for agitating gas-liquid mixture flowing through said throat for separating gas therefrom and delivering the gas free liquid under pressure to said outlet, spaced support columns extending upwardly from said tapered throat, a piston chamber carried by said columns, a pistonin said chamber, a second tapered throat connected to said piston and movable therewith toward and away from said rst tapered throat, said second Vtapered throat having a flow opening therethrough smaller than said i'lrst throat, pressure means on one side of said pistonrfor normally maintaining said throat members in spaced relation, and conduit Imeans connecting the other side of said piston and said discharge volute whereby the discharge pressure in said pump maintains said throat members in engagement when the discharge pressure exceeds that of said pressure means.

10. A centrifugal booster pump for a fuel system for separating gas from a gas-liquid mixture, comprising a casing defining a discharge volute, an inlet and an outlet for said volute, a stationary throat member in said inlet, an impeller adjacent said throat mem-ber and having vane blades overlapped by the periphery of the throat opening in said member, said impeller agitating gas-liquid mixture flowing through said throat member for separating gas therefrom and delivering the gas-free liquid under pressure to said outlet, support columns on said throat member, a movable throat member sized for seating on and extending into said stationary inlet throat to restrict the throat opening into the pump and increase the overlapping of the vane blades to thereby increase the discharge pressure of liquid pumped by the blades, guide means on said columns for guiding said movable throat member, piston means for moving said movable guided throat member toward and away from said stationary throat member, and conduit means hydraulically connecting said discharge volute andfsaid piston means whereby the movement of said movable throat member is controlled by the discharge pressure in said volute.

11. A centrifugal booster pump for a fuel system for separating gas from a gas-liquid mixture, comprising a casing defining a discharge volute, an inlet and an outlet for said volute, a rotatable impeller adjacent said inlet, relatively movable throat members in said inlet overlapping the periphery of saidimpeller, each of said throat members deilning a different size inlet opening for varying the overlapping of said impeller to thereby change the discharge pressure of said pump, a piston cylinder, a piston in said cylinder, conduit means connecting said discharge volute and one end of said piston cylinder, and a coil spring between the other end of said piston cylinder and said piston for normally maintaining said throat members in spaced relation, said piston moving and maintaining said vlutefvar.inletgland'an outlet for said volute, a

ned by one of the throat members, and-means controlled lsby the changes;- in discharge pressure Yof said pump :for ,relatively -moving said :throat members into and out of said telescopic engagement. l`\.

13. A liquid pump assembly comprising a throat member defining an inlet opening to the pump, a second throat member movable toward and away from said first throat member for dening a different size inlet opening to the pump, an impeller overlapped by said throat members,

means for driving said impeller, a multi-speedcontrol device for said driving means, and means controlled by the discharge pressure of saidpump for moving said second throat member, said throat members being spaced when the discharge pressure of said pump is below a predetermined value and being maintained in engagement for' decreasing the size of the inlet opening to the pump and increasing the overlapping of said impeller when the discharge pressure exceeds said predetermined value.

14. A liquid pump assembly comprising a throat member dening an inlet opening to the pump. a second throat member movable toward and away from said first throat member for dening a different size inlet opening to the pump, an impeller overlapped by said throat members, an electric motor for driving said impeller, an electrical supply source for energizing and de-energizing said motor, rheostat means for varying the speed of the -moton and means controlled by the discharge pressure of said pump for moving said second throat member, said throat members being spaced when the discharge pressurey of said pump is below a predetermined value and being moved into and maintained in engagement for decreasing the size of the inlet opening to the pump and increasing the overlapping of said impeller when the discharge pressure `exceeds said predetermined value.

l5. In a centrifugal pump assembly including an impeller, a suction inlet, and a passageway adjacent said inlet receiving the impeller, the improvement which comprises a device for changing the size of said inlet and thereby changing the length of said passageway.

16. In a pump assembly having a housing dening an inlet and an outlet, a rotatable impeller between said inlet and said outlet having vanes thereon defining with said housing movable means for restricting the size of said inlet and increasing the length of said channels to enhance the pumping capacity of said pump.

17. A liquid pump assembly comprising a throat ring dening an inlet opening to the pump, a second throat ring movable toward and away from said rst throat ent size inlet opening to the pump, a rotatable impeller overlapped by said throat rings, and control means sensitive to variations in the discharge pressure of the pump for controlling the relative movement of said throat rings, said control means including pressure exerting means for maintaining said second throat ring away discharge I ring for defining a differ- "pressure exertedby A with agitating vanes uncovered alongfrom said 'throat ringfwhen thedischarge of the pnmpv said last means, said control means beingl elective for moving andgmaintaining said second throat rin'g in' engagement with said nrst throat ring when` thev discharge pressure of` said pump exceeds `the pressure exerted by saidgiast means.- Y' s l 18. In a pump assembly having `au inlet, an

isless than the pressure t their lengths exposed to the inletl together i with pumping vanes covered alongtheir-lengths to denneLwaiis of pumping channels for reoeiv f the ngitatinz increasing ing v material toi bepumped from vanes.' landmeans y for simultaneously the covered lengths of decreasing the uncovered lengths oi the agitatn ing vanes'to thereby increase ofthe pumping channels.

' n RUSSELL R. CURTIS.

said pumping vane: while 1 the eiective lengths f 

